In a beta attenuation densitometer, a shock wave to be measured is passed between a radioactive source and a detector. The increase in density in the shock wave causes a decrease in the amount of radiation reaching the radiation detector. The detected radiation is converted to light in a scintillator crystal, and the light is converted to an electrical signal in a photomultiplier, the electrical signal becoming the system output.
Existing densitometers of the type in question have some deficiencies for use in high pressure shock waves because of the severe conditions encountered. The present invention aims at the provision of an improved densitometer for use in exceptionally severe conditions, including overpressures of up to 1040 kPa.